Telephone transmission system wherein reinforcing-repeaters are employed.



ALBERT SIMON JonAN VAN KESTEREN; or vL ssmGEn, NETHERLANDS.

TELEBHONE TRANSMISSION sfzsrnn WHEREIIT BEINFORCING-REPEATERS AREEMPLOYED.

Specification of Ltters Patent.

Patented July 4, 1916;

Application filed December 19, .1913. Serial No. 807,749,

To 117 l wit-mu it 112 (11 concern Be it known that l. ALBERT SumsJonas: YAX Kizs'rnmix, a subject of the Queen of the Netherlands. andresiding at- Vlissingen, Province of Zeeland. Xetherlands, have inventedcertain new and useful Improvements in and Relating to TelephoneTransmission Systems \Vherein Reinforcing-l epea-ters Are Employed, ofwhich the following is a specification.

This invention relates to telephone transmission systems comprisingrepeaters for reinforcing the current wavesbetween two subscribers?stat-ions.

According to this invention, a long dis tance; line for conversation ineach direction between the stations is provided, which two lines areconnected at their ends to each other and also to lines leading tov eachsubscribers station, the latter connections being positive or inductive,while the total damping of the two lines between the points ofconnection is made equal to,-or greater than the total reinforcingproduced by the repeater or repeaters. This arrangement allowsconversation in both directions to be carriedon, without itbeing'nccessaryto balance portions of the lines, or use reversingswitchesi v p Figure 1} of the accompanying drawing showsdiagrammatically an, unsuitable system subject to the so-called buzzingor howling,. Fig. 2' shows a system according tothis invention, with onerepeater for each; tall;- ing direction. Fig. shgowsa system. withseveral repeaters for each; talking. direction. Fig. 41 shows a systemaccordingto this in.-

vention. with one-relay only for both direc-' tions of talking.

Inthe system according to Fig- 1, which has not proved satisfactory inpractice, the repeaters T,,.T; areins'ertediintheline c-c ata pointintermediatethe talking stations C and D. It was held that. the talkingcurby therepea'ter T so that it becomes audible at station D, and thatthe talking current produced at D, is strengthened by therepeater Tsothat it becomes audible at staaction. is diiferent. The talkingcurrent emanating from T, divides at the junction m, and one portionreaches thereceiver a, of the repeater T appears strengthened at b and 1divides at. the junction 2 part then going rent prod'ucedf at stationisstrengthened 60110. It has been found, however, that the through. a,into the repeater T and being transmitted reinforced tob and so on. Theresult is that buzzing is heard in the receivers of. the subscriber'sstations, and the system is unsatisfactory. i

Fig. 2 shows a system according to this nvention.v In a long distanceline comprising the parts L and L a repeater T is inserted of which a,is the receiving and b the transmitting side. The repeater T thustransmits talking'currents only in the direction. from station A tostation B. The sec- 0nd line L and L transmits talking currents only inthe direction from B to A, as

the repeater T is arranged with its receivlng side a, connected tostation B, and'its transmitting side 6 connected to station A- zitpoints and q the sending and receiving lines are connected to each otherand to lines leading tothe subscribers stations. The

connections tothese latter may be either direct or inductive. The linesg.A and pB may be themselveslong distance lines, so that the pointsp andg need not be near in Fig.1, will. appear in the system shown.

in 2",. as any current wave circulating in the circuit q, L,,, T 11,,12,. L '18,, p

rapidly diminishes to zero value, as it is being: constantly damped to agreater extent, than it is reinforced.

If-xthodamping! in the line L L should be smaller than the reinforcingin said line then. in order that there should be no inadmissible howlingcurrents, the reinforcing in the line L L must be smaller by at least.the same extent than the damping in the same line. In this case, at thepoint 9,

talking currents arrive which are stronger than those set out from thepoint p. At.

thepoint p, on the cont'rary,currents are received which are weaker thanthe currents sent out fromthe point 9.

It follows from the foregoing that the lines L L, and 11,. L. need notbe balanced.

As the talking currents passing through the points 7) or 9, after havingpassed through the long distance lines, are received at the points 9 orp with little or no Weakening. the lines between A and g or between Band 1) may be of considerable length.

Fig. 3 shows an arrangement in which a number of repeaters T and '1 areinserted at arbitrary points in the long distance lines L and L Theabove mentioned rule applies also here, so that the total reinforcing bythe repeaters T and T may at the outside be equal to the total dampingin the lines L, and L between the points 79 and 9.

Fig. 4 shows a system in which the reinforcing can be effected by meansof a single repeater. In this arrangement it is necessary to insert therepeater T between two long distance lines L, and L at such a distancefrom the junction points 79 and 9 that neither of the two circuits onthe right and left hand side of the repeater T the damping will besmaller than the reinforcing. These two circuits of course need not bebalanced. If the damping of the current waves in one of the two circuitssituated laterally of the relay T were less than the reinforcing by therepeater T howling would take place, as described above with referenceto Fig. 1. Apart from the fact that the system of Fig. 4 is not so goodas the system of Figs. 2 and 3, owing to the situation of the repeater Tbeing incapable of much variation, the system-of Fig. 4 is lessefficient than the first described two systems.

The double wire lines illustrated may be obviously replaced by singlewire lines with earth return, without departing from the invention, andthe invention can be used in systems other than those diagrammaticallyillustrated.

aving thus described my invention, what I claim is: I

1. In a telephone system comprising at least one repeater forstrengthening the current waves between two subscriber stations, a linefor conversation in each direction between said stations, the saidseparate lines being electrically connected at the ends to each otherand also to each subscribers station, the said lines being of suchextent that the damping therein between the two points of connection isequal to, or greater than, the total strengthening produced by the repeater.

2. A telephone transmission system comprising in combination, a pair ofparallel lines connected at the ends to each other and also to linesgoing to each subscribers station, and repeaters placed in said linesand so arranged that one line is used only for transmission in onedirection and .so that the total damping in a closed circuit composed ofsaid parallel lines is greater than the total reinforcing of therepeaters.

In testimony whereof I affix my signature in presence of two witnesses.

ALBERT'SIMON JOHAN VAN KESTEREN.

lVitnesses:

' J. A. HOOGIIAMEN,

CHR. F. Knnnsnx NEKER.

Copies of thil patent may be obtained for five cents each, by addressingthe "comlilsioner of Intent,

Wmhingtm, n. c."

